[Nut-upsuser] ordered shutdown

Marco Chiappero marco at absence.it
Mon Feb 9 12:44:34 UTC 2009

Arjen de Korte ha scritto:
> Citeren Lars Täuber <taeuber at bbaw.de>:
>> it seems I understood how NUT works now. But then it is not the  
>> solution for us. The reason simply is we have one big ups for so  
>> many servers. And it's a bad idea to have one point in time to  
>> shutdown all servers. So one »battery low« signal for all servers is  
>> not what we need.
> In that case, I probably don't understand what you're trying to do.

I think I know what he meant, because my needs are similar. I already 
explained them some time ago, when I discovered that NUT comes with no 
features at all about programmable outlets (right now I still have no 
shutdown sequence settled yet).
When you have one ups and many computers with different needs the "low 
battery" signal starts having no use (well, it can be useful but just 
for the last computers you want to shut down).
Let's assume I have one big UPS, some clients and a couple of servers. 
Now suppose that we want some clients to shut down immediately, as they 
are not important, but some not, maybe when it's clear that it's a 
serious outage (and we prefer to save power for the servers). So I would 
trigger shutdown for the first clients when battery charge is 95% (just 
to be sure it's not a realy short and temporary outage) and when charge 
is 50-60% for the second ones. Finally I'd like to start the powerdown 
sequence for the two servers when 15-20% charge is reached. That's the 
problem, and in the problem description there's no need to indicate a 
low battery value. We can use it for the servers but who cares, it's not 
important the name you attribute to the 20% charge level. About the 
clients, upssched it's not the right way for doing this, in my opinion.
 From my standpoint, the computer owning and controlling the UPS should 
be a director/conductor, should order who have to shutdown and when. In 
case of programmable outlets it should also manage them considering who 
is connected to which port. "Clients" should just accept orders, ack 
them and report the start of the sequence. Is it wrong? Am I missing 

> So you want the servers to keep running as long as possible and the  
> clients should go down after a power outage of (say) five minutes?  
> That's possible too.

In my opinion that's a limitation and, again in my humble opinion, poor 
design. It sounds like refuelling a car on a $TIME schedule rather than 
an avaiability basis: I use to refuel when the *real* remaining fuel is 
below a certain value/charge, do you use to refuel on a *supposed* fuel 
consumption over $TIME?
In a complex senario it can help much in both having easy configuration 
and successful shutdown sequence.

At the moment my MGE UPS is powering on programmable outlets after some 
time, while it should consider battery charge (to be enought for another 
power outage). About NUT: no powershare support, no different shutdown 
based on battery charge. Many good ideas, nothing really useful to me 
till now. :(
My 2 cents.

Marco Chiappero

More information about the Nut-upsuser mailing list